Low thermal conductivity and high mechanical strength of piezoelectric ceramics

Piezoelectric ceramics are mainly used to guide special piezoceramics with low thermal coefficient and poor heat transfer. The thermal insulation piezo ceramics mainly use zirconia and alumina ceramic materials. The zirconia materials have low thermal conductivity and are used as thermal insulation products. The effect is very good, more and more piezo ceramic products have selected zirconia ceramics for heat insulation,piezo ceramic disc transducer uses alumina as the main raw material, adding 6-30% of sintering accelerators such as clay, magnesium oxide, calcium oxide, and titanium oxide, and mixing and sintering at a temperature of 1450 ~ 1800 ° C. The more alumina content, the more the inherent characteristics of alumina can be exerted, and the better  performance, but it also becomes difficult to manufacture as the alumina content increases. Alumina porcelain is characterized by good insulation properties at high temperatures. Pure alumina porcelain can be used at a temperature of 800 °C. Its mechanical strength is higher in all oxide-based ceramics, its thermal conductivity is large, thermal shock resistance and strong ability, which can be used to manufacture spark plug insulators, insulation parts for ultra-high-frequency high-power electric vacuum devices, electronic tube and rectifier shells, integrated circuit substrates, etc.

The structural parts of piezoelectric discs crystal are mostly white, but the piezo ceramic material will turn to goose yellow after being illuminated by sunlight. There are two reasons for the discoloration of white alumina piezoceramics. One is that deliquescent of alumina ceramics has occurred, resulting in hydrated alumina. Another possibility is that some components in alumina piezo ceramics have changed in the high temperature environments. For example, titanium oxide is an oxide that will change color with high temperature, and this change process is irreversible. In summary, it seems that the discoloration of alumina ceramics is caused by the oxidation of the material. In addition to piezoceramics, other materials also have this characteristic. This phenomenon is generally difficult toavoid.Piezoelectric ceramic ingredients are pre-material treatment, remove impurities and moisture, and then weigh various raw materials according to the formula ratio, pay attention to the small amount of additives to be placed in the middle of the bulk.